From: Borislav Petkov <bp@alien8.de>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>,
Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org, Dave Hansen <dave.hansen@intel.com>,
Chang Seok Bae <chang.seok.bae@intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Sasha Levin <sashal@kernel.org>,
kvm@vger.kernel.org, Tom Lendacky <thomas.lendacky@amd.com>
Subject: Re: [PATCH] x86/entry/64: Disallow RDPID in paranoid entry if KVM is enabled
Date: Fri, 21 Aug 2020 11:22:37 +0200 [thread overview]
Message-ID: <20200821092237.GF12181@zn.tnic> (raw)
In-Reply-To: <3b4ba9e9-dbf6-a094-0684-e68248050758@redhat.com>
On Fri, Aug 21, 2020 at 11:05:24AM +0200, Paolo Bonzini wrote:
> ... RDTSCP is used as an ordered rdtsc but it discards the TSC_AUX
> value.
... and now because KVM is using it, the kernel can forget using
TSC_AUX. Are you kidding me?!
> Hence the assumption that KVM makes (and has made ever since TSC_AUX was
> introduced.
And *this* is the problem. KVM can't just be grabbing MSRs and claiming
them because it started using them first. You guys need to stop this. If
it is a shared resource, there better be an agreement about sharing it.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2020-08-21 9:22 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-21 2:50 [PATCH] x86/entry/64: Disallow RDPID in paranoid entry if KVM is enabled Sean Christopherson
2020-08-21 7:24 ` peterz
2020-08-21 7:44 ` Borislav Petkov
2020-08-21 7:47 ` Borislav Petkov
2020-08-21 8:09 ` Paolo Bonzini
2020-08-21 8:16 ` Borislav Petkov
2020-08-21 9:05 ` Paolo Bonzini
2020-08-21 9:22 ` Borislav Petkov [this message]
2020-08-21 9:44 ` Paolo Bonzini
2020-08-21 9:48 ` Borislav Petkov
2020-08-21 10:07 ` Paolo Bonzini
2020-08-22 16:42 ` Andy Lutomirski
2020-09-16 16:54 ` Paolo Bonzini
2020-08-21 9:28 ` Thomas Gleixner
2020-08-21 9:37 ` Paolo Bonzini
2020-08-21 19:55 ` hpa
2020-08-21 20:02 ` Peter Zijlstra
2020-08-21 8:56 ` kernel test robot
2020-08-21 8:56 ` kernel test robot
2020-08-21 10:28 ` kernel test robot
2020-08-21 10:28 ` kernel test robot
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